Active agents, e.g., pharmaceuticals, nutraceuticals, and the like, intended for oral administration are often provided in solid form as tablets, capsules, pills, lozenges, or granules. Oral dosage forms are swallowed whole, chewed in the mouth, or dissolved sublingually. Chewable dosage forms are often employed in the administration of active agents where it is impractical to provide a tablet for swallowing whole, where it is desirable to make an active agent available topically in the mouth or throat for both local effects or systemic absorption and to improve drug administration in pediatric and geriatric patients. With chewable dosage forms, the act of chewing disperses the particles of the dosage form and may increase the rate of absorption of any active agent present therein.
It has been observed that particles in chewable dosage forms leave a gritty sensation in the mouth that can be unpleasant, i.e., unpleasant mouthfeel. The term mouthfeel relates to the type of sensation or touch that a dosage form produces in the mouth upon ingestion and is not concerned with the chemical stimulation of olfactory nerves or taste buds. However, for a dosage form to be successful, the overall effect in the mouth is important. In general, a gritty texture is undesirable. A smooth texture is preferred. See, Pharmaceutical Dosage Forms, Edited by Leiberman, H. A. and Lachman, L. Marcel Dekker, Inc. New York, Volume 1, pp. 291.
In attempts to address some of the above issues, different formulations have been investigated. Formulations of nano- or macrogranulars have been reported in U.S. Pat. No. 5,618,527. In order to prevent the sensation of grittiness, U.S. Pat. No. 5,618,527 describes formulations in either liquid or tablet form consisting of spherical particles of not greater then 125 μm in diameter. Additionally, the particles are required to have smooth edges. These requirements severely limit the flexibility of delivery of the drug.
Another method of is described in U.S. Pat. No. 6,077,557. This patent describes incorporating a calcium component into a gel. In particular, the grittiness of the calcium component was avoided by utilizing a calcium source having a small particle size, 90% of the calcium particles being less than 150 μm and the best results were described as being obtained with a mean particle size of less than 50 μm.
An alternative attempt to reduce the sensation of grittiness by using a blend of a gritty drug product with a seedy fruit, such as strawberries, was described in U.S. Pat. No. 5,102,664. In this combination, the seedy fibrous fruit texture masks the grittiness of the active agent.
It is known to apply outer coatings to a chewable tablet in order to protect the soft core. Often such outer coatings contain cellulose derivatives as major ingredients, which have relatively high melting points, i.e., greater than 135° C. For example, PCT Application No. WO 93/13758 discloses the application of a thin layer of coating material such as a disaccharide, polysaccharide, or cellulose derivative onto a compressed tablet. U.S. Pat. No. 4,828,845 relates to the coating of a comestible with a coating solution comprising xylitol, a film-forming agent such as methyl cellulose, a binder, optionally a filler, and optionally a plasticizer such as polyethylene glycol, the balance of the solution being water. The plasticizer makes up only about 3 to 7 weight percent of the coating solution disclosed in the '845 patent. U.S. Pat. No. 4,327,076 discloses a compressed, soft, chewable tablet containing an antacid or other active agent that may be coated with a sealant or a spray coat of chocolate.
U.S. Pat. No. 6,017,567 discloses a sugar-free hard coating of edible, chewable, or pharmaceutical compositions. In particular, the hard coating was disclosed as being formed by treating a core with a sorbitol syrup and at least one other polyol in crystalline form. In particular, the hard coating of disclosed was believed to be useful for coating chewing gum, confectionery products (such as candies), chocolate and nuts.
Alternatively, as disclosed in U.S. Pat. No. 4,684,534, moisture-free soft tablets have been produced by compressing a combination of an active agent with a carbohydrate and a binder such that the open pore structure of the combination is destroyed only at the tablet surface. Because of their relatively brittle exterior, these tablets are resistant to moisture absorption; however, these tablets quickly liquefy and melt when chewed due to their open pore interior structure.
Yet another method for preparing soft cores in food products is disclosed in U.S. Pat. No. 5,362,508, wherein a core composition comprising a mixture of sucrose, invertase, and a fat component is coated with a second fat component. Upon incubation, short chain fatty acid residues from the second fat component migrated into the core fat component to yield a soft fat mixture in the core having a lower fat solids content.
A dosage form has now been discovered that masks the grittiness of the active agents contained therein. This dosage form not only effectively masks the taste and texture of the active agent, but it conveniently may be consumed anywhere without the need for water. The dosage form includes a soft core encased in a brittle coating. Surprisingly, the brittle coating of the present invention not only stabilizes the soft core, but it also provides a masking agent for the gritty texture of the active agent upon chewing